Now showing items 1-20 of 28

    • Compact size highly directive antennas based on the SRR metamaterial medium 

      Bulu, I.; Caglayan, H.; Aydin, K.; Ozbay, E. (Institute of Physics Publishing, 2005)
      In this work, we studied the far-field properties of the microwave radiation from sources embedded inside the split-ring resonator (SRR) metamaterial medium. Our results showed that the emitted power near the resonance ...
    • Development of micro-structured metamaterials for innovative antenna layouts 

      Bilotti F.; Capolino F.; Gonzalo, R.; Özbay, Ekmel; Romeu J.; Schuchinsky, A.; Tretyakov, S.; Vardaxoglou, Y. (IEEE, 2007)
      In this paper, we present the joint activities developed in the frame of the FP6 European Network of Excellence METAMORPHOSE in the field of new micro-structured materials for antenna applications. One of the key scientific ...
    • Enhanced transmission of microwave radiation in one-dimensional metallic gratings with subwavelength aperture 

      Akarca-Biyikli, S. S.; Bulu, I.; Ozbay, E. (American Institute of Physics, 2004)
      We report a theoretical and experimental demonstration of enhanced microwave transmission through subwavelength apertures in metallic structures with double-sided gratings. Three different types of aluminum gratings ...
    • Evaluating spatial diversity technique for mitigating multipath fading of fixed terrestrial point-to-point systems 

      Goktas P.; Topcu, S.; Karasan, E.; Altintas, A. (Institute of Electrical and Electronics Engineers Inc., 2015)
      Multipath fading is the dominant propagation factor for fixed terrestrial microwave line-of-sight (LOS) radio links operating at frequencies below 10 GHz. Fading due to multipath propagation attenuates received signals on ...
    • Experimental observation of cavity formation in composite metamaterials 

      Caglayan H.; Bulu I.; Loncar, M.; Ozbay, E. (Optical Society of American (OSA), 2008)
      In this paper, we investigated one of the promising applications of left-handed metamaterials: composite metamaterial based cavities. Four different cavity structures operating in the microwave regime were constructed, and ...
    • Experimental observation of left-handed transmission in a bilayer metamaterial under normal-to-plane propagation 

      Guven, K.; Caliskan, M.D.; Ozbay, E. (Optical Society of American (OSA), 2006)
      We demonstrate experimentally the double-negative (ε < 0, μ < 0) transmission band of a one-dimensional metamaterial structure under normal-to-plane propagation in the microwave regime. The structure consists of stacked ...
    • Fabrication and characterisation of solar-blind Al0.6Ga0.4N MSM photodetectors 

      Biyikli, N.; Kimukin, I.; Tut, T.; Aytur, O.; Ozbay, E. (The Institution of Engineering and Technology, 2005)
      Solar-blind metal-semiconductor-metal (MSM) photodiodes based on MOCVD-grown Al0.6Ga0.4N template have been fabricated and tested. AlGaN detector samples were fabricated using a microwave compatible fabrication process. ...
    • Ferroelectric based tuneable SRR based metamaterial for microwave applications 

      Ozbay, E.; Aydin, K.; Butun, S.; Kolodziejak, K.; Pawlak, D. (2007)
      We discuss the possibility of achieving tunable split ring resonators at microwave frequencies. One method is to use varying capacitance values to tune the magnetic resonance frequency. As another method ferroelectric thin ...
    • High bandwidth-efficiency solar-blind AlGaN Schottky photodiodes with low dark current 

      Tut, T.; Biyikli, N.; Kimukin, I.; Kartaloglu, T.; Aytur, O.; Unlu, M. S.; Ozbay, E. (Pergamon Press, 2005-01)
      Al0.38Ga0.62N/GaN heterojunction solar-blind Schottky photodetectors with low dark current, high responsivity, and fast pulse response were demonstrated. A five-step microwave compatible fabrication process was utilized ...
    • High-performance solar-blind AlGaN Schottky photodiodes 

      Biyikli, N.; Kartaloglu, T.; Aytur, O.; Kimukin, I.; Ozbay, E. (Materials Research Society, 2003)
      High-performance solar-blind AlGaN-based Schottky photodiodes have been demonstrated. The detectors were fabricated on MOCVD-grown AlGaN/GaN heterostructures using a microwave-compatible fabrication process. Current-voltage, ...
    • High-Speed Solar-Blind AlGaN Schottky Photodiodes 

      Biyikli, N.; Kimukin I.; Kartaloglu, T.; Aytür O.; Ozbay, E. (2003)
      We report high-speed solar-blind AlGaN-based Schottky photodiodes. AlGaN/GaN heterostructure device layers were grown on sapphire substrate. The devices were fabricated on AlGaN/GaN heterostructuresusing a microwave ...
    • InGaAs-based high-performance p-i-n photodiodes 

      Kimukin, I.; Biyikli, N.; Butun, B.; Aytur, O.; Ünlü, S. M.; Ozbay, E. (IEEE, 2002-03)
      In this letter, we have designed, fabricated, and characterized high-speed and high efficiency InGaAs-based p-i-n photodetectors with a resonant cavity enhanced structure. The devices were fabricated by a microwave-compatible ...
    • Interference analysis of fixed terrestrial microwave LOS/NLOS radio links 

      Goktas P.; Topcu, S.; Karasan, E.; Altintas, A. (Institute of Electrical and Electronics Engineers Inc., 2015)
      In this study, interference modelling is investigated for fixed terrestrial microwave LOS (line-of-sight)/ NLOS (transhorizon) radio links operating in NATO Band 3+ (1350-2690 MHz) and NATO Band 4 (4400-5000 MHz) frequency ...
    • Light-controlled microwave whispering-gallery-mode quasi-optical resonators at 50W LED array illumination 

      Yurchenko V.B.; Ciydem, M.; Altintas, A. (American Institute of Physics Inc., 2015)
      We present experimental observations of light-controlled resonance effects in microwave whispering-gallery-mode quasi-optical dielectric-semiconductor disk resonators in the frequency band of 5 GHz to 20 GHz arising due ...
    • Low-frequency time-domain characterization for fast and reliable evaluation of microwave transistor performance 

      Bosi G.; Raffo A.; Vadalà V.; Trevisan F.; Vannini G.; Cengiz, Ömer; Şen, Özlem; Özbay, Ekmel (IEEE, 2016)
      In this paper, we introduce the use of the low-frequency characterization of electron devices as an accurate and economical way to fast gather consistent data about the electron device performance at microwaves in the ...
    • Low-voltage small-size double-arm MEMS actuator 

      Biyikli, N.; Damgaci, Y.; Cetiner, B.A. (2009)
      The fabrication and characterisation of a double-arm cantilever-type metallic DC-contact MEMS actuator with low pull-down voltage are reported. Bi-layer TiW cantilevers with an internal stress gradient were fabricated using ...
    • Microwave transmission through metamaterials in free space 

      Aydin, K.; Bayindir, M.; Ozbay, E. (2002)
      To investigate properties of metamaterials, composite structures which consists of periodical arrangement of thin copper wires and SRRs on a circuit board was constructed. Through this, the transmission properties of ...
    • Miniaturization and characterization of metamaterial resonant particles 

      Aznar F.; Bonache J.; Martín F.; Ozbay, E.; Alici, K. B.; Bilotti, F.; Tricarico, S.; Vegni, L.; Baena J.D.; Jelinek L.; Marqués, R. (2008)
      This paper is focussed on the miniaturization and characterization of semi-lumped resonators, of interest for the synthesis of metamaterial-based structures such as metamaterial transmission lines, frequency selective ...
    • Observation of negative refraction and negative phase velocity in left-handed metamaterials 

      Aydin, K.; Guven, K.; Soukoulis, C. M.; Ozbay, E. (American Institute of Physics, 2005)
      We report the transmission characteristics of a two-dimensional (2D) composite metamaterial (CMM) structure in free space. At the frequencies where left-handed transmission takes place, we experimentally confirmed that the ...
    • Physics and applications of photonic nanocrystals 

      Ozbay E.; Guven K.; Aydin K.; Bayindir M. (2004)
      Photonic nanocrystals are periodic dielectric or metallic structures having photonic bands in analogy to electronic bands of semiconductors. The presence of photonic band-gaps, where the propagation of photons of certain ...